Hemoglobin A1c-related histologic characteristics of symptomatic carotid plaques
M Tecellioglu1, S Alan1, S Kamisli1
1Department Pathology, School of Medicine, Inonu University, Malatya, Turkey.
Insights
Elevated glycosylated hemoglobin (HbA1c) is linked to thinner fibrous cups in carotid plaques, increasing stroke risk. This study highlights HbA1c
Area of Science:
- Cardiovascular Research
- Endocrinology
- Neurology
Background:
- Carotid artery stenosis is a significant risk factor for ischemic stroke.
- Glycosylated hemoglobin (HbA1c) levels are associated with stroke risk.
- Histomorphological characteristics of carotid plaques require further investigation in relation to HbA1c.
Purpose of the Study:
- To compare histomorphological features of carotid plaques with HbA1c levels in patients undergoing carotid endarterectomy.
- To identify specific plaque structures affected by elevated HbA1c in symptomatic cases.
- To elucidate the relationship between glycemic control and carotid plaque stability.
Main Methods:
- Retrospective evaluation of 64 patients with ischemic stroke and no prior diabetes diagnosis.
- Microscopic assessment of carotid plaques by two pathologists, analyzing parameters like plaque rupture, lipid core, fibrous cup thickness, and inflammation.
- Classification of patients into four groups based on HbA1c levels: normal/prediabetes, effectively controlled, less effectively controlled, and uncontrolled.
Main Results:
- A negative correlation was observed between patient age and HbA1c levels.
- Fibrous cup thickness significantly decreased as HbA1c levels increased across the groups.
- No significant differences were found in other plaque instability parameters (rupture, lipid core, inflammation, etc.) among HbA1c groups.
Conclusions:
- Increased HbA1c levels are associated with a thinner fibrous cup in carotid plaques, suggesting a mechanism for increased plaque instability.
- Fibrous cup thickness is the primary histomorphological feature of carotid plaques affected by HbA1c.
- These findings underscore the importance of glycemic control in managing carotid artery disease and preventing ischemic stroke.
Background:
The aims of our study were to compare the histomorphological characteristics of carotid plaques and glycosylated hemoglobin (HbA1c), which are risk factors for ischemic stroke, in patients who underwent carotid endarterectomy for carotid artery stenosis. Moreover, we aimed to identify the structures that were histologically affected by symptomatic carotid plaques in cases with elevated HbA1c.
Materials And Methods:
A total of 64 patients who presented with ischemic stroke and had not previously been diagnosed with diabetes were retrospectively evaluated. All stroke risk factors were reviewed. Carotid plaques were graded separately by two different pathologists through microscopic assessment of the following parameters: plaque rupture, lipid core, fibrous cup thickness, inflammation, intraplaque hemorrhage, thrombus, calcification, necrotic core, and neovascularization. An HbA1c value <6.3% was accepted as normal or indicative of prediabetes (group 1), whereas patients with values ranging between 6.3-7.4%, 7.5-8.4%, and >8.4% were categorized into the effectively controlled (group 2), less effectively controlled (group 3), and uncontrolled (group 4) groups, respectively.
Results:
The mean age of the patients was 73.0 ± 4.5 years in group 1, 69.7 ± 2.3 years in group 2, 66.0 ± 8.5 years in group 3, and 62.7 ± 7.1 years in group 4. A negative correlation was present between age and HbA1c. Smoking, hypertension, low-density lipoprotein cholesterol levels, and triglyceride levels were not significantly different among the four groups. According to the HbA1c classifications, the fibrous cup thickness was 2.64 ± 0.3 mm in group 1, 1.85 ± 0.4 mm in group 2, 1.68 ± 0.5 mm in group 3, and 1.45 ± 0.6 mm in group 4. The fibrous cup became thinner as the HbA1c value increased. Other parameters of unstable carotid plaques did not differ among the HbA1c groups.
Conclusions:
Increased HbA1c values seem to contribute to plaque instability through the formation of a thin fibrous cup. Thus, of the carotid artery plaque parameters including fibrous cup thickness, plaque rupture, lipid core, inflammation, intraplaque hemorrhage, thrombus, calcification, necrotic core, and neovascularization, fibrous cup thickness is the only histomorphological feature that affected by HbA1c.
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